Preparation of carbonaceous adsorbents for removal of chloroform from drinking water

Abstract

Microporous carbons for use as adsorbents in removing chloroform from drinking water were prepared by activating charcoals made from the following natural raw materials: evergreen oak ( Q. phillyraeoides), bamboo ( P. pubescens), coconut shell ( C. nucifera), and Japanese cedar ( C. japonica), and from dehydrochlorinated vinylidene film. Chloroform adsorption was found to be enhanced by increase in the specific surface area of the microporous carbon, but suppressed by enlargement of micropore-size. This suppression is due to a decrease in the interaction, governed by London dispersion force, between the chloroform molecules and the pore walls of the microporous carbon. Carbon with iodine adsorption capacity of around 760 mg g −1 demonstrated the greatest chloroform adsorption regardless of the raw material used. In order of chloroform adsorption amount, the materials ranked as follows: vinylidene film>Japanese cedar>coconut shell≒evergreen oak>bamboo. The carbon produced by 30 min dehydrochlorination of vinylidene film and that produced by 50 min steam activation of Japanese cedar charcoal demonstrated adsorption capacities several times higher than that of commercial activated carbon.